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Cine Meter for iPhone: faq copyright © 2013-2014 Adam J. Wilt  
 
A light meter with a waveform monitor and a false-color picture
 
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I can't find Cine Meter in the App Store! Where is it?

Are you searching on an iPad running iOS 6 or later? By default, the App Store on iPad only shows iPad apps. Select “iPhone Apps” at the top of the screen, and Cine Meter should appear.

How do I manually set exposure and white balance?

I’m sorry, there is no manual mode: iDevice cameras didn't allow it before iOS 8, and Cine Meter hasn't been reworked to allow it. Instead you have to lock the auto-exposure and auto-white-balance settings while looking at something with the proper exposure and white balance, like a gray card. See How To for details.

How big is the spot meter's spot?

It depends on your iDevice camera’s angle of view. On my iPod touch 4G, it’s about 10º.

Can I change the size of the spot metering area?

No, sorry. It’s set by the camera in your iDevice, and it isn't adjustable. 

Can Cine Meter measure color temperature?

No. When Cine Meter was written, iDevice cameras did not report any color temperature or white balance information other than "white balance locked" or "white balance unlocked", so there's no way to find out what the real color of the scene is.

Why doesn’t the light meter match my DSLR / handheld meter?

Cine Meter computes exposure based on the standard APEX equation, using the assumed EXIF values for K and N. Its default calibration matches my Spectra Pro IV and Gossen Starlite meters very closely. However, it may not match your meters:

Why no incident meter mode?

Incident readings require incident light sensors, which iDevices lack. Cine Meter uses the iDevice’s camera. Like any other camera, it's a reflected-light sensor.

In theory one could turn an iDevice camera into an incident sensor by mounting a spherical diffuser or photosphere — one of those ping-pong-ball-lookalike domes — in front of the camera, but that’s not something I can do in software alone. Cine Meter II allows incident readings using just such a device, but Cine Meter is for reflected light only.

You can shoot an 18% gray card with Cine Meter to get the same result as an incident meter would give you (though you may want to open up 1/2 stop from the reflected reading to match your incident meter’s reading).

Where’s the lux/footcandle reading?

It can’t be done with a reflected meter; not properly. Lux and footcandles are measures of light illuminating an object, not the light reflected from it.

The folks making Pocket Light Meter found that people were improperly using the lux/fc readouts in an early version of their app to judge emergency lighting installations and for other life-safety applications, so they had to take those measurements out. Let’s not go there...

Where is the Android version?

I haven’t written it yet! Android cameras (most of them, at least) don't provide brightness-value metadata, only camera-exposure metadata, making it much harder to calculate an accurate exposure value: camera exposure can vary by as much as a stop from the "correct" value depending on how the camera is programmed. However, I may have a workaround for that, though I'll need to test it before I can say for certain. Stay tuned...

How do I upgrade to Cine Meter II?

If you have purchased Cine Meter, look for Cine Meter Upgrade Bundle in the App Store, and select “Complete My Bundle” to save $4 (USA) over the cost of buying Cine Meter II by itself. [Note: Bundles don’t show up in the App Store app on iOS 6 or earlier; you’ll need to use iTunes on your computer to see it, or upgrade your iDevice to iOS 7 or later.]

I'm a student: can I get a discount?

Both Cine Meter and Cine Meter II are eligible for the educational volume purchase program. Your school can buy 20 or more at half price, and give you a code to install it on your iDevice. Details at http://www.apple.com/education/it/vpp/

Why isn’t my question answered here?

Because I haven’t heard it yet, that's why. Ask me and I’ll see if I can answer it.



© 2013-2014 Adam J. Wilt.  Last updated 2014.10.18